An encore presentation of this ABC News "Nightline" report will air on July 4 at 12:37 a.m. ET

Lindsay Ess added more and more weights to the barbell. As a newbie to CrossFit competition, one of her goals was to pull 73 pounds with one arm.

During a recent competition, she wasn’t able to reach her goal, but that didn’t stop her. Ess kept trying and by the end of the day, she had set a new personal record of deadlifting 85 pounds with one arm.

“I didn’t want to leave until I did that,” the 32-year-old told “Nightline.”

But what was more remarkable than her athletic ability is the fact that, five years ago, Ess had lost all her limbs to infections. She has had several transplants, including unusual and still-experimental double hand-transplant surgery.

Now, she is using her transplanted hands and forearms for everything -- including deadlifting weights at CrossFit.

“If you can imagine lifting a barbell from the ground with arms that are not yours, that are attached by rods that are sewn on by stitches,” she said.

A quadruple amputee, Lindsay lost her hands and feet to a sepsis infection eight years ago. Her arms had to be amputated just below the elbow. So simple tasks, such as feeding herself, washing her hair and putting on her prosthetic legs, became impossible without help and she relied heavily on her mother.

After struggling with prosthetic arms, Lindsay exercised diligently for years to qualify for a double hand transplant. In September 2011, two separate teams of surgeons at the University of Pennsylvania hospital, one for the right arm and one for the left, worked for nearly 12 hours to perform a cutting-edge operation to give her new hands.

"The first couple of days I refused to look at them," Ess said in a 2013 “Nightline” interview. "It was kind of like one of those scary movie moments. I'm too scared to look because it's reality [but] I'm so grateful to have them that I just don't really think about it superficially."

In a few months after having surgery, Lindsay made remarkable progress. Her doctors saw she could extend and move her wrists and fingers, begin to sense hot and cold and even pick up lightweight objects ahead of schedule.

Although the prognosis for both hands could not have been better, Lindsay suffered setbacks along the way. When it looked like her body might be rejecting the transplants, the former model and aspiring fashion show producer had to have her steroid dose increased. The steroids caused her to gain more than 40 pounds, which she found discouraging.

But her therapy continued and Lindsay grew stronger. The darker pigment in the donor arms faded away and the excess skin and fat placed in her arms to prevent her body from rejecting the transplants was surgically removed.

Another small sign of success was that her intrinsic muscles, the little muscles that contract and flex the fingers, were working.

"Before I could brush my teeth and it was difficult," she said in a previous interview. "Now I can brush my teeth and it's easy."

She still has a ways to go, but she has made tremendous progress and she got back the thing she wanted most – her independence.

“I drive. I live on my own. I have a dog. House, to take care of. Cleaning. Dishes. Cooking,” she said, adding that there are still some things she needs help with.

“I can’t put my hair up, or button blouses or jeans. Tie shoes,” Ess continued. “So if I have to do changes of shoes, or want my hair a specific way obviously my mom helps me.”

Her situation has inspired her to want to help others with disabilities, including wounded veterans, with whom she competed with at the CrossFit competition. CrossFit and hours and hours of workouts have not only made her muscles stronger but have also given her a new lease on life.

“I think that if you don’t take chances in life, big chances, then big things aren’t going to happen,” she said. “So it’s been working so far for me. So why kind of stop now?”